Synthesis, molecular docking and biological evaluation of novel phthaloyl derivatives of 3-amino-3-aryl propionic acids as inhibitors of Trypanosoma cruzi trans-sialidase.

In the last two decades, trans-sialidase of Trypanosoma cruzi (TcTS) has been an important pharmacological target for developing new anti-Chagas agents. In a continuous effort to discover new potential TcTS inhibitors, 3-amino-3-arylpropionic acid derivatives (series A) and novel phthaloyl derivatives (series B, C and D) were synthesized and molecular docking, TcTS enzyme inhibition and determination of trypanocidal activity were carried out. From four series obtained, compound D-11 had the highest binding affinity value (-11.1 kcal/mol) compared to reference DANA (-7.8 kcal/mol), a natural ligand for TS enzyme. Furthermore, the 3D and 2D interactions analysis of compound D-11 showed a hydrogen bond, π-π stacking, π-anion, hydrophobic and Van der Waals forces with all important amino acid residues (Arg35, Arg245, Arg314, Tyr119, Trp312, Tyr342, Glu230 and Asp59) on the active site of TcTS. Additionally, D-11 showed the highest TcTS enzyme inhibition (86.9% ±â€¯5) by high-performance ion exchange chromatography (HPAEC). Finally, D-11 showed better trypanocidal activity than the reference drugs nifurtimox and benznidazole with an equal % lysis (63 ±â€¯4 and 65 ±â€¯2 at 10 µg/mL) and LC50 value (52.70 ±â€¯2.70 µM and 46.19 ±â€¯2.36 µM) on NINOA and INC-5 strains, respectively. Therefore, D-11 is a small-molecule with potent TcTS inhibition and a strong trypanocidal effect that could help in the development of new anti-Chagas agents.

An in vitro and in vivo evaluation of new potential trans-sialidase inhibitors of Trypanosoma cruzi predicted by a computational drug repositioning method.

Chagas disease is one of the most important neglected parasitic diseases afflicting developed and undeveloped countries. There are currently limited options for inexpensive and secure pharmacological treatment. In this study, we employed a structure-based virtual screening protocol for 3180 FDA-approved drugs for repositioning of them as potential trans-sialidase inhibitors. In vitro and in vivo evaluations were performed for the selected drugs against trypomastigotes from the INC-5 and NINOA strains of T. cruzi. Also, inhibition of sialylation by the trans-sialidase enzyme reaction was evaluated using high-performance anion-exchange chromatography with pulse amperometric detection to confirm the mechanism of action. Results from the computational study showed 38 top drugs with the best binding-energies. Four compounds with antihistaminic, anti-hypertensive, and antibiotic properties showed better trypanocidal effects (LC50 range = 4.5-25.8 µg/mL) than the reference drugs, nifurtimox and benznidazole (LC50 range = 36.1-46.8 µg/mL) in both strains in the in vitro model. The anti-inflammatory, sulfasalazine showed moderate inhibition (37.6%) of sialylation in a trans-sialidase enzyme inhibition reaction. Sulfasalazine also showed the best trypanocidal effects in short-term in vivo experiments on infected mice. This study suggests for the first time that the anti-inflammatory sulfasalazine could be used as a lead compound to develop new trans-sialidase inhibitors.